Control system for torpedo steering



Aug. 8, 1961 P. G. EDWARDS 2,995,100

CONTROL SYSTEM FOR TORPE-DO STEERING Filed June 2, 1944 IWDROPI-IONEENABLE)? 44 [.3 HYDROPHOAESW REJOLWNG RUBBER CIRCUIT CONTROL I nuoomFIG. 2

k B E 5 I E 3" 4 E A TA 2 v TIME lNVE/VTOR P. GEDWARDS WW6 jdia/LATTORNEY Patented Aug. 8, 1961 2,995,100 CONTROL SYSTEM FOR TORPEDOSTEERING Paul G. Edwards, Verona, N..I., assignor to Bell TelephoneLaboratories, Incorporated, New York, N.Y., a corporation of New YorkFiled June 2, 1944, Ser. No. 538,525 11 Claims. (Cl. 114-23) Thisinvention relates to control systems and more particularly toanti-countermining protective systems for torpedoes having controlcircuits of the type disclosed in the application Serial No. 538,435filed June 2, 1944, of Alton C. Dickieson.

A torpedo having a control circuit of the form disclosed in theapplication above identified comprises, in general, a normally disabledsteering system for guiding the torpedo to a target, such as a ship, inaccordance with signals emanating from the target, and a trigger circuitfor enabling the steering system when a ship comes within the effectiverange of the torpedo after the latter is launched. The trigger circuitoperates in response to sonic signals received at a hydrophoneconstituting the input element of the circuit and is so constructed andarranged as to discriminate against background submarine noises andtarget signals of other than a prescribed character, whereby itfunctions to enable the steering system only in response to receipt atthe hydrophone of signals characteristic of ships having such speedsthat the torpedo can overtake them. In a specific circuit, thediscrimination is effected on the basis of propeller frequencies, thepropeller frequency of a ship being a measure of the ships speed, andthe enabling of the steering system is brought about by operation of acontrol relay in the output circuit of an amplifier energized inaccordance with a potential derived from the output of the hydrophone,the relay, when operated, serving to cause energization of a controlelement for an enabler associated with the steering system.

One object of this invention is to prevent false enabling of a torpedosteering system of the signal controlled, sonically triggered type. Morespecifically, one object of this invention is to prevent operation of asubmarine signal responsive control circuit by explosion waves, such asare produced by mines in countermining operations.

In one illustrative embodiment of this invention, a control circuit ofthe' general form and organization described above comprises a delayelement for allowing operation of the control element only after elapseof a prescribed interval after operation of the control relay and asecond relay is provided energized in series with the control relay, thesecond relay being less sensitive than the control relay and effectivewhen operated to cause disabling of the trigger control circuit. The tworelays are constructed and arranged so that when the amplifier input isin accordance with ships signals received by the hydrophone the intervalbetween operation of the two relays is greater than the delay intervalaforenoted whereby the control relay is effective to cause enabling ofthe steering system, but when the amplifier input is in accordance withexplosion waves received by the hydrophone, the interval betweenoperation of the two relays is less than the delay interval aforenoted,whereby the second relay is eifective to disable the trigger circuitbefore the steering system can be enabled as a result of operation ofthe control relay.

The invention and the various features thereof will be understood moreclearly and fully from the following detailed description with referenceto the accompanying drawing in which:

FIG. 1 is a circuit diagram, partly in functional schematic form, of acontrol system for a torpedo illustrative of one embodiment .of thisinvention, and

FIG. 2 is a graph illustrating the relation between relay currents andtime for both ship signal and explosion waves received by the hydrophonein the trigger circuit shown in FIG. 1.

Referring now to the drawing, the control system in FIG. 1 comprises asteering system, which may be of the construction disclosed in theapplication Serial No. 491,- 795, filed June 22, 1943 of Donald D.Robertson, including hydrophones 10 for receiving signals emanating froma target, e.g. ship, a resolving circuit 11 for converting thehydrophone outputs into a potential related in amplitude and polarity tothe angle and direction of the target with respect to the torpedo, and acontrol element 12 actuated in accordance with this potential fordeflecting the rudder 13 to guide the torpedo to the target. Theresolving circuit normally is inoperative and has associated therewithan enabler 14 controlled by a trigger control circuit.

The trigger control circuit, which may be of the general form describedin detail in the application of Alton C. Dickieson identifiedhereinabove, comprises a hydrophone 15 the output of which is fed to anamplifier 16 and then demodulated by a demodulator 17, for example ofthe copper oxide disc type. The amplifier 16 is provided with anautomatic volume control including a condenser 18 and a resistance 19.The low frequency demodulation components are amplified by a suitablelow frequency amplifier 20 and supplied to two channels each of whichincludes a filter 21 followed by an amplifier 22 and a detector 23. Thetwo channels are blanced for background or random submarine noise andone of the filters is of the low-pass type and the other of theband-pass type as indicated in FIG. 1. The direct current outputvoltages of the detectors 23 are combined in opposing relation andapplied to the input circuit of a direct current amplifier 24 whichnormally is biased beyond cut-off. The output circuit of the amplifierincludes a relay 25 which when operated effects actuation of the enabler14 in a manner described in detail hereinafter.

In brief, the general operation of the system is as follows: After thetorpedo is launched, an anchor therein is released automatically to moorthe torpedo at a preassigned depth. At this time, the steering andpropelling systems for the torpedo are disabled. The trigger circuitalso is disabled but is rendered operative automatically at apreassigned interval after the launching of the torpedo. After thisinterval, when a ship having an envelope of noise of prescribedcharacter comes Within the effective range of the torpedo, the triggercircuit operates to energize the enabler and the latter causes theanchor to be cast off and renders the steering and propelling systemsoperative whereby the torpedo is guided to the ship. The details ofoperation are set forth fully in the aforementioned applications. It maybe pointed out, however, that the filters serve to prevent operation ofthe trigger circuit by background submarine noise and by ships thepropeller frequencies of which correspond to ship speeds so great thatthe torpedo could not overtake the ship. More particularly, thepass-band of the low-pass filter embraces only those frequenciescharacteristic of the propeller frequencies of ships that the torpedocan overtake and the two signal channels are so constructed and arrangedthat the direct current amplifier 24 will have sutficient output currentto cause operation of the relay 25 only when the direct current voltageof the channel including the lowpass filter exceeds that of the otherchannel to a preassigned extent.

The control or actuating system for the enabler 14 compriss a relay 26which is connected in the output circuit of an electron discharge device27. The grid of this device normally is biased beyond cut-off by asuitable source 28, such as a battery, over the circuit including a pairof resistances 29 and 30 and the armature 31 and 3 contact 32 of therelay 25. The grid circuit of the device 27 includes also a condenser 33bridged by a resistance 34.

Normally, that is when the relay 25 is not energized, the device 27 isblocked and the condenser 33 is charged through the resistances 29 and39. When the relay 25 is energized, the armature 31 engages the othercontact 35 and the condenser 33 discharges through the resistance 34 ata rate determined by the constants of this resistance and the condenser.After an interval, determined by these constants, the bias upon the gridof the device 27 decreases sufficiently to render the device conductiveand cause operation of relay 26 to energize the enabler 14.

If, after the relay 25 operates and during the interval noted, thesignals received by the hydrophone 15 are such as to render theamplifier 24 non-conducting, the armature 31 transfers from contact 35to contact 32 and the condenser begins to charge at a rate determined bythe resistances 29 and 30, and the bias on the grid of the device 27 isincreased accordingly. It will be seen then, that in order that therelay 26 may operate, it is necessary that the armature 31 be disengagedfrom the contact 32 for a certain fraction, determined of course by theconstants of the charging and discharging circuits for the condenser 33,of a preassigned period. In a typical system these constants may be suchthat the armature be disengaged from the contact '32 at leastfour-fifths of the time during a five second period in order that thedevice 27 may cause operation of the relay 26, substantially fiveseconds after the relay 25 is first energized. Specifically, the voltageof source 28 may be 10.5 volts, the condenser 33 of 2 microfaradcapacity and the resistances 30, 34 and 29 of 1.5 megohms, 2.7 megohmsand 130 ohms, respectively, for a device 27 of the 3Q4 type operatedwith a plate voltage of 67.5 volts. Thus, as will be apparent, operationof the enabler 14 by transient signals even of such character as torender the amplifier 24 conductive momentarily, and false operation ofthe system by such signals are prevented.

It will be noted that when the relay 25 is in its nonoperated state, thecathode or heater for the device 27 is extinguished so that the powerdrain is small. When the relay operates, the cathode heater circuit isclosed directly through the resistance 29.

It will be appreciated that because of the character of the triggercontrol circuit, principally its operation in response to low frequencysignals, the circuit as thus far described might be operated falsely byexplosion signal waves such as are produced during counterminingoperations, although some measure of protection against such waves isprovided by the delay system, above described, associated with thedevice 27. To protect the system further against false operation by suchwaves, means are provided, in accordance with a feature of thisinvention, for disabling the trigger circuit when explosion signals arereceived by the hydrophone 15.

As shown in FIG. 1, a second relay 36 is provided in series with therelay 25 and the anode supply source 37 for the direct current amplifier24, the relay 36 being desensitized as by a shunt resistor 38. When theamplifier 24 is rendered conductive, the current through the relay 36will increase at a lesser rate than that through the relay 25 and, thetwo relays being otherwise similar, the relay 25 will operate some timebefore the relay 36. The relay 36 has its armature 39 and contact 40 incircuit with the source 28 and the AVG for the amplifier 16 so that whenthe relay 36 operates the amplifier 16 is paralyzed and the triggercircuit is thus disabled.

The rate of current increase in the two relays is dependent upon thecharacter of the input to the hydrophone 15 and, in general, issubstantially slower for signals due to a ship approaching within rangeof the torpedo than for signals due to explosions in the vicinity of thetorpedo. The general relation between time and relay current isillustrated in FIG. 2. In this figure, the operating currents for therelays 25 and 36 are indicated by the lines A and A respectively; therelation between relay currents and time for current due to ship signalsreceived by the hydrophone 15 is indicated by the line B; and thecurrent-time relation for relay currents due to explosion signalsreceived by the hydrophone 15 is indicated by the curve C.

The relay 36 is so desensitized, as by the shunt resistor 38, that theinterval between the operate times, T and T for the two relays inresponse to ship signals is greater than the delay interval, for example5 seconds in the specific case given above, provided by the delayelement 33, 34. The interval between the operate times, T and T for thetwo relays in response to explosion waves is less than the delayinterval, for example 5 seconds, provided by the delay element.

When the two relays are operated in response to ship signals, the relay25 operates first and after the delay interval the enabler 14 isoperated and the steering system is enabled. Once enabled, the steeringsystem remains enabled, so that subsequent operation of the relay 36,that is after the elapse of a period greater than the delay intervalfollowing operation of the relay 25, has no eifect upon the steeringsystem. However, if the relays are actuated in response to explosionwaves received by the hydrophone 15, the interval between operation ofthe relay 25 and subsequent operation of the relay 36 is so short thatthe amplifier 16 is paralyzed before the elapse of the delay intervalbetween operation of the relay 25 and functioning of the device 27requisite for energization of the enabler. Hence, false enabling of thesteering system by explosion waves is prevented. Specifically, in suchcase, the relays 25 and 36 release when the amplifier 16 is paralyzed sothat the condenser 33 is charged and the delay element is reset. Thecharge placed upon the condenser 18 by operation of the relay 36 leaksoff gradually when this relay releases following disabling of theamplifier 16 so that the trigger circuit is reset after a preassignableinterval following receipt of explosion waves by the hydrophone.

Although a specific embodiment of the invention has been shown anddescribed, it will be understood that it is but illustrative and thatvarious modifications may be made therein without departing from thescope and spirit of this invention as defined by the appended claims.

What is claimed is:

1. A control system for a torpedo having normally disabled steeringmeans, said system comprising a hydrophone, a trigger circuit for whichthe hydrophone constitutes the input element, responsive to noiseemanating from a ship for enabling said steering means, and means fordisabling said circuit when explosion noise is received by saidhydrophone.

2. A control system for a torpedo having normally disabled steeringmeans, said system comprising a submarine signal detector, an operatingmeans for enabling said steering means, an energizing circuit for saidoperating means for which said detector constitutes the input element,and means for disabling said circuit when explosion submarine signalsare received by said detector.

3. A control system for a torpedo having normally disabled steeringmeans, said system comprising a hydrophone, a trigger circuit for whichsaid hydrophone constitutes the input element and including relay means,operating means responsive to operation of said relay means for enablingsaid steering means, means for delaying operation of said operatingmeans for a preassigned interval after operation of said relay means,and means for disabling said circuit during said interval when explosionsignals are received by said hydrophone.

4. A control system for a torpedo having normally disabled steeringmeans, said system comprising an enabler for said steering means, meansfor actuating said enabler,

control means for said actuating means, an energizing circuit for saidcontrol means, a hydrophone constituting the input element for saidcircuit, a delay element associating said actuating and control meansfor delaying operation of said actuating means for a prescribed intervalafter energization of said control means, and means for disabling saidenergizing circuit in response to receipt by said hydrophone of signalsincreasing in intensity at greater than a preassigned rate.

5. A control system comprising normally disabled operating means, meansfor enabling said operating means, actuating means for said enablingmeans, a hydrophone, a first relay, a second relay less sensitive thansaid first relay, means for energizing said first and second relays incommon in accordance with the output of said hydrophone, means forenergizing said actuating means in response to operation of said firstrelay, and means for disabling said relay energizing means in responseto operation of said second relay.

6. A control system comprising a hydrophone, a first relay, a secondrelay less sensitive than said first relay, an energizing circuit forwhich said hydrophone constitutes the input element and in which saidrelays are serially connected, an operating means, means including adelay network for energizing said operating means at a preassignedinterval after operation of said first relay, and means for disablingsaid energizing circuit in response to operation of said second relay,the operating levels of said first and second relays being such that fora maximum prescribed rate of increase in output of said hydrophone thetime between operation of said first and second relays is greater thansaid preassigned interval.

7. A control system comprising an operating element, a hydrophone, andmeans for enabling said operating element only in response to submarinesignals received by said hydrophone increasing in intensity at less thana preassigned rate, said means comprising a first relay, a second relay,means for energizing said operating element in response to operation ofsaid first relay at a prescribed interval after operation of said firstrelay, means for energizing said relays in common in accordance with theoutput of said hydrophone, means responsive to operation of said secondrelay for disabling said relay energizing means, and means fordesensitizing said second relay so that the interval between operationof said first and second relays in response to signals received by saidhydrophone and increasing in intensity at less than said pre' assignedrate is greater than said prescribed interval.

8. A control system for a torpedo having normally disabled steeringmeans, said system comprising a hydrophone, an amplifier, saidhydrophone constituting the input element for said amplifier, a relay inthe output circuit of said amplifier, means for enabling said steeringmeans, an energizing circuit for said enabling means, means for closingsaid energizing circuit in response to and at a preassigned intervalafter operation of said relay, and means for disabling said amplifierwithin said interval when explosion noises are received by saidhydrophone.

9. A control system in accordance with claim 8 wherein said disablingmeans comprises a second relay energized in series with and lesssensitive than said first relay such that for outputs of said hydrophonedue to noise emanating from ships the interval between operation of saidfirst and second relays is greater than said preassigned interval.

10. A control system comprising an operating element, a signal detectingdevice, an amplifier for which said device constitutes the inputelement, a relay connected to the output of said amplifier, a controlcircuit for said operating element including an electron dischargedevice having a control grid and cathode, a source for normally biasingsaid control grid beyond cut-ofi, and means for rendering said deviceconducting in response to operation of said relay only when said relayremains operated for a certain portion of a prescribed interval afterinitial operation of said relay, said last means comprising a condenserconnected between said cathode and said control grid, a charging circuitfor said condenser including said source and a first resistance and adischarging circuit for said condenser including a second resistanceseparate from said charging circuit, said relay being arranged to opensaid charging circuit when operated.

11. A control system in accordance with claim 10 comprising means fordisabling said amplifier when signals of a certain character arereceived by said detecting device, said disabling means comprising asecond relay energized in series with said first relay and of lesssensitivity than said first relay such that for signals of saidcharacter the interval between operation of said first and second relaysis less than said prescribed interval.

References Cited in the file of this patent UNITED STATES PATENTS1,312,510 Baker Aug. 12, 1919

